PCOS: What the Diagnosis Means and What Actually Helps
Polycystic ovary syndrome is one of the most common hormonal conditions in women of reproductive age, and one of the most confusingly named. The cysts are not cysts, you do not need them for the diagnosis, and the central problem is often metabolic rather than ovarian.
How it is diagnosed
The widely used Rotterdam criteria require two of the following three, with other causes excluded:
- Irregular or absent ovulation. Usually showing as cycles longer than 35 days, fewer than eight periods a year, or no periods.
- Clinical or biochemical hyperandrogenism. Excess male-pattern hair growth, acne, or male-pattern hair thinning, or raised androgen levels on blood tests.
- Polycystic ovarian morphology on ultrasound. Many small follicles, or increased ovarian volume.
Two of three. This means you can have PCOS with completely normal-looking ovaries, and you can have polycystic-looking ovaries with no PCOS at all. The appearance is common in healthy young women, particularly in the late teens, which is why ultrasound is not recommended for diagnosis within eight years of the first period.
The “cysts” are actually immature follicles that stalled rather than ovulating. They are not cysts in the usual sense and do not need removal.
Other conditions must be excluded first: thyroid disease, raised prolactin, non-classical congenital adrenal hyperplasia, and in some presentations Cushing syndrome.
The insulin connection
A large proportion of women with PCOS have insulin resistance, independent of weight, though excess weight worsens it.
The mechanism links the pieces together. High insulin stimulates the ovaries to produce more androgens, and lowers sex hormone binding globulin in the liver, which raises the proportion of free, active testosterone. Higher androgens disrupt follicle maturation, so ovulation becomes irregular, and produce the acne and hair changes.
This is why metabolic treatment often improves the reproductive symptoms, and why PCOS carries long-term risks of type 2 diabetes, gestational diabetes, fatty liver, high blood pressure and abnormal lipids. Those risks are the reason PCOS is a lifelong health matter rather than a fertility issue alone.
Why irregular periods need addressing even without pregnancy plans
When ovulation does not occur, the uterine lining is exposed to oestrogen without the balancing progesterone that follows ovulation. Over years, that unopposed stimulation increases the risk of endometrial hyperplasia and endometrial cancer.
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General practice is that a woman with PCOS should have at least around four periods a year, induced if necessary with hormonal treatment. Simply having no periods and no symptoms is not a benign situation.
Treatments, by what you want to achieve
For irregular cycles and endometrial protection: combined oral contraceptives, cyclical progestogens, or the levonorgestrel intrauterine system.
For excess hair and acne: combined oral contraceptives, anti-androgens such as spironolactone with reliable contraception, topical treatments, and physical methods such as laser hair reduction, which is more effective than repeated temporary measures.
For fertility: letrozole is now the first-line ovulation induction agent, having outperformed clomiphene in trials. Metformin is sometimes added. Gonadotropins, ovarian drilling and IVF follow if needed.
For metabolic health: this is the foundation.
- Weight reduction of 5 to 10 per cent, where there is excess weight, can restore ovulation in a substantial proportion of women, improve androgen levels and reduce metabolic risk. It is among the most effective interventions available
- Resistance training and aerobic exercise, which improve insulin sensitivity independently of weight change
- Metformin, which improves insulin sensitivity and can help cycle regularity
- Inositol, specifically myo-inositol, sometimes with D-chiro-inositol, with reasonable evidence for improving insulin sensitivity and ovulation, and a good safety profile
- GLP-1 receptor agonists, increasingly used where obesity is a major factor
No single diet has been proven superior. Lower glycaemic load patterns and adequate protein suit the underlying physiology, and the diet people can sustain is the one that works.
Screening to ask for
- Oral glucose tolerance test or HbA1c, repeated periodically, and in early pregnancy
- Blood pressure
- Lipid profile
- Liver function, given the association with fatty liver
- Screening for depression and anxiety, which are considerably more common in PCOS and are frequently overlooked
- Assessment of sleep apnoea if there is snoring and daytime sleepiness
What does not help
- Ovarian cyst removal surgery, since these are follicles and not cysts requiring removal
- Supplements marketed as PCOS cures without evidence
- Blanket elimination diets
- Being told simply to lose weight with no support, which is both unhelpful and unkind, particularly since insulin resistance makes weight loss harder
Fertility, in perspective
PCOS is a leading cause of ovulatory infertility, and also one of the most treatable. Many women conceive with lifestyle change alone or with letrozole. Equally, irregular cycles do not mean no ovulation ever, so contraception is still needed when pregnancy is not wanted.
The short version
PCOS is diagnosed by two of three criteria, so the ultrasound is optional and often misleading in young women. Insulin resistance sits underneath most of it, which is why metabolic treatment improves reproductive symptoms. Even without pregnancy plans, cycles should be regulated to protect the uterine lining, and metabolic screening should be ongoing rather than one-off.